Animated texture that depends on camera perspective
Using WINDOW TEXTURE COORDINATE
Use a Window texture coordinate for mapping. Adjust Location, Rotation and Scale parameters of the Mapping node to make the texture fit the object borders.



Using UV PROJECT MODIFIER
Subdivide your cube a few times and unwrap it (I've marked seams and then unwrapped).

Add the UV Project Modifier. Set up your image texture, set the Camera as a projector. If the image doesn't display correctly adjust the Aspect values.